The Internet has grown and continues to grow dramatically, and the wealth of information available on the Internet is enormous. In order to take advantage of this wealth of information, a key enabler is a web search engine. A web search engine is a tool that enables a user to request a search for web pages or media such as songs, pictures and movies, on the Internet that contain designated search terms, and that responds by providing a summary with links to web pages thus found. Without a search engine, the Internet would be like a library with millions of books shelved in random order, and without an index system to reference them.
Today, very sophisticated and powerful search engines exist, such as the search engine of Google, Inc. of Mountain View, Calif., and the search engine of Yahoo!, Inc. of Sunnyvale, Calif., which enable a user to search millions of web pages for designated search terms, and media such as pictures, songs and movies, within seconds.
Because the Internet is a public network, there is no natural screening in place for content placed on the web. Instead, special screening tools such as content filters are used to filter out undesired content. One of the most vital filters is a content security filter, which blocks content containing viruses or other such malicious program code from being downloaded and wreaking havoc in a user's computer. Content security filters are described in Applicants' U.S. Pat. Nos. 6,092,194 and 6,804,780, both entitled SYSTEM AND METHOD FOR PROTECTING A COMPUTER AND A NETWORK FROM HOSTILE DOWNLOADABLES, pending U.S. Ser. No. 10/930,884, entitled METHOD AND SYSTEM FOR ADAPTIVE RULE-BASED CONTENT SCANNERS, and pending U.S. Ser. No. 11/298,475, entitled SYSTEM AND METHOD FOR INSPECTING DYNAMICALLY GENERATED EXECUTABLE CODE, all of which are incorporated by reference.
Like the Internet, conventional search engines have no natural screening in place, and the web pages and media located by a search engine in its search results may contain content that poses security risks. If a user does not have a security filter in place on his computer, then he may compromise his computer security by clicking on one of the links displayed in a search results summary. Even if the user does have a security filter in place, which blocks his computer from downloading unsafe content, he may still click on links to web pages with unsafe content, which are then blocked by his content filter. If his filter is not continually updated, then the filter may not be able to block all types of unsafe content. If his filter is continually updated, then the filter will block unsafe content, but the user will waste time clicking on links in search results that reference web pages or media with unsafe content, and then having these web pages or media blocked by the filter. This may waste, for example a few seconds of time for each unsafe link displayed in the search results. Given that users regularly sift through hundreds of search engine results on a daily basis, the waste of time is significant.